Writing pen



FIG. 1 is a front perspective view of a writing pen showing my new design with the cap placed on the end remote from the writing point;

FIG. 2 is a front elevational view thereof with the cap placed over the writing point;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a right end view of FIG. 2;

FIG. 5 is a left end view of FIG. 2; and

FIG. 6 is a top plan view of FIG. 2. 

The ornamental design for a writing pen, as shown and described. 